Evolve lower IV Shadow (1-2 star) or Higher IV normal (3 star minimum)

Ive comeback in like august 25 into the game, been playing for some time, trying to collect as many high IVs as i can, but now in starting to look for raid battle, and I know that Shadow pokemons are stronger with attacks and everything, but in curious, bcs for example i have a 2star Shadow bagon and normal 92% 3 star bagon, and i dont have enought mega energy to compesate for missing the “Shadow effect” on a normal pokemon. I mainly wanna be able to be as strong as possible in raid, bcs pvp doesnt bother me so, is it better to have a lower IV Shadow pokemons or Higher IV normal pokemon ? Thanks and good luck in Road to Kalos 🙏